This invention relates to a cooking system, and more particularly to a system for frying frozen or refrigerated foods and a burner which is especially adapted for use in cooking systems and similar applications.
As is well known, hamburger stands, fried chicken stands, and similar convenience restaurants usually sell various fried food items including French fried potatoes, fried fish, and the like. These items are typically supplied to a convenience restaurant in frozen form and are cooked at the restaurant directly from the frozen state, that is, without being first thawed or otherwise prepared for cooking. It is therefore necessary to equip each convenience restaurant with a system for frying frozen or refrigerated foods.
Although various frying systems suitable for use in convenience restaurants and the like have been proposed heretofore, a number of problems have remained unsolved. Thus, many prior art frozen food frying systems have comprised a frypot having fire tubes extending through its lower portion. Such a system achieves good heat transfer to cooking oil in the frypot but is inconvenient to clean because it is difficult to gain access to the area around the fire tubes in order to remove wastes and residues that have accumulated during cooking. One attempt to overcome this problem has been to provide an externally heated cooking container. However, many of the externally fired containers that have been proposed heretofore have not achieved efficient heat transfer and have therefore been relatively expensive to operate.
The present invention comprises a cooking system which overcomes the foregoing and other deficiencies that have long been associated with the prior art. In accordance with the broader aspects of the invention, a frypot includes heat transfer walls each comprising a lower vertically extending portion and an upper outwardly extending portion. Combustion is established in zones located adjacent the vertically extending portions so that heated products of combustion travel upwardly along the vertically extending and the outwardly extending portions of the heat transfer walls. By this means very efficient heat transfer is effected through the heat transfer walls to cooking oil in the frypot.
An important factor in the efficient heat transfer that is achieved in cooking systems employing the present invention is the vertical orientation of the lower portion of the heat transfer walls. It has been found that if a heat transfer wall for a frypot has a substantial horizontal component, a boundary layer of heated cooking oil tends to form along the wall, whereupon further heat transfer through the wall is retarded by the boundary layer. On the other hand, if the heat transfer wall is substantially vertical, circulation of the cooking oil due to natural convection continuously removes the boundary layer.
Another important aspect of the invention comprises a novel burner which is especially adapted for use in cooking systems and similar applications. The burner comprises structure for discharging two or more gas jets into a combustion zone in such directions that at least portions of the jets of gas and the air they entrain contact or intersect with each other. This causes turbulent intermixing of the gas with the ambient or secondary air. A target is positioned at least partially in the path of the interacting jets to deflect the jets and thereby cause further intermixing of the gas and the air. The target also reflects heat into the combustion zone to increase the efficiency of the burner and also through the heat transfer walls.
In accordance with more specific aspects of the invention, the frypot comprises opposed heat transfer walls which are spaced to permit easy cleaning of the frypot. Baffles may be provided for retarding heat transfer into the portion of the frypot below the vertically extending portions of the heat transfer walls and thereby providing a relatively cool zone in the bottom of the frypot for receiving breading particles and other solid wastes that accumulate during cooking. Baffles are also mounted adjacent each heat transfer wall above the combustion zones and beneath the outwardly extending portion of the heat transfer walls for preventing recycling of the products of combustion into the combustion zones.